I really want that 450hp Allison(!!!) but it would be at least a $250K
upgrade and I have a 80hr engine now. Supposedly it well take off in about
80' with the Allison..

Mike
MU-2


"Jim Burns" wrote in message
...
Thanks Mike!
Great explaination of desired airflow vs. HP.
Several years ago our aerial applicators mounted gearboxes and longer
props
to their round engined Air Tractors. Not only did they reduce the prop
speed and noise but they increased the airflow around the airplane
produceing a better spray pattern.

Jim


No, Helio owners only care about STOL performance. The Helio requires
high
power for takeoff only. Actually what it requires is high static thrust
and
it benefits from a large diameter prop so that thrust flows over more of
the
slats/wing/flaps. The geared engine can use a larger diameter prop
without
the tips going supersonic. Once airborn, the airplane is not going to go
very fast (135-140kts) with its large wing and large exposed wheels no
matter how much power is availible.